Preparation:

Step 1: Prepare the Cake Batter

1. Preheat your oven to 325°F (163°C). Grease a 10-inch Bundt pan thoroughly and lightly dust it with flour to prevent sticking.
2. In a large mixing bowl, whisk together the dry ingredients: flour, sugar, salt, baking powder, and baking soda.
3. Add the softened butter, buttermilk, eggs, and vanilla extract to the dry mixture. Using a hand mixer or stand mixer, beat the ingredients on low speed until combined. Increase the speed to medium and mix until the batter is smooth and creamy, about 3-4 minutes.

Step 2: Bake the Cake

1. Pour the batter evenly into the prepared Bundt pan, smoothing the top with a spatula.
2. Bake in the preheated oven for 55-65 minutes, or until a toothpick inserted into the center comes out clean.
3. Once baked, allow the cake to cool in the pan for 10 minutes, then carefully invert it onto a wire rack.

Step 3: Prepare the Butter Sauce

1. While the cake cools slightly, make the butter sauce. In a small saucepan over medium heat, melt the butter, sugar, and water, stirring until the sugar dissolves completely.
2. Remove the pan from heat and stir in the vanilla extract.

Step 4: Soak the Cake

1. Poke small holes all over the surface of the cake using a skewer or toothpick.
2. Slowly pour the warm butter sauce over the cake, allowing it to soak in completely. Be sure to pour gradually so the sauce absorbs evenly.

Step 5: Make the Salted Caramel Sauce

1. In a medium saucepan, heat the sugar over medium heat, stirring constantly with a heatproof spatula until it melts into a smooth amber liquid.
2. Add the cubed butter carefully (it will bubble up) and whisk until fully incorporated.
3. Slowly pour in the heavy cream while whisking continuously. Continue to whisk until the caramel is smooth.
4. Remove from heat and stir in the sea salt. Allow the sauce to cool slightly before drizzling over the cake.

Step 6: Final Assembly

1. Once the cake has absorbed the butter sauce, transfer it to a serving platter.
2. Generously drizzle the salted caramel sauce over the top of the cake, letting it cascade down the sides.
3. For an extra touch, sprinkle a pinch of sea salt over the caramel.